Abstract: An information processing apparatus/method employs error detection or correction to encode information to be distributed in a description format used in a multimedia network in which the error detection or correction encodes at least a portion in the header in the information to be distributed with higher redundancy than the entity in the information to be distributed. The encoded information to be distributed in a broadcast signal is multiplexed and transmitted. Alternatively, the information processing apparatus/method may involve: transmitting a portion of the header in the information to be distributed at least a plurality of number of times while the entity in the information to be distributed is transmitted; and/or transmitting a plurality of kinds of information as an entity in the information to be distributed, and using different error detection or correction ability in correspondence with the kind of information.

Abstract: A two-dimensional scanning device constructed with first deflector to deflect a collimated beam, second deflector to deflect an incident beam in the direction orthogonally intersecting the deflecting direction of the first deflector, a scanning lens interposed between the first and second deflectors, a scanning plane to focus a scanning beam from the scanning lens through the second deflector, and an expedient to obtain a distortion-free two-dimensional scanning pattern on the scanning plane by rotating the scanning plane around a rotational axis in the direction orthogonally intersecting the deflecting direction of the second deflector in synchronism with rotation of the second deflector.

Abstract: In a semiconductor laser optical system which uses a light source a semiconductor laser having different diverging points and divergence angles in orthogonal directions and in which the light beam from the light source is imaged on a scanned surface, only a spherical surface optical system is provided between the semiconductor laser and the scanned surface. The spherical surface optical system includes two partial optical systems, i.e. a first image forming optical system and a second image forming optical system as viewed from the light source side. By selecting the optical constant of one of the two image forming optical systems to a predetermined value, the peak power of the image forming spot on the scanned surface is maximized.

Abstract: A two-dimensional scanning apparatus is disclosed which includes first deflector for deflecting a collimated beam, second deflector for deflecting the incident beam in the direction orthogonal to the direction of deflection by the first deflector, a scanning lens disposed between the first and second deflector, a surface to be scanned on which an image of the scanning beam is formed through the second deflector and a device for moving the scanned surface in the direction orthogonal to the surface in synchronism with the rotational motion of the second deflector so as to obtain a two-dimensional, distortionless scanning pattern on the scanned surface.

Abstract: A two-dimensional scanning device provided with a first deflector for deflecting a collimated beam, a second deflector for deflecting the incident beam in a direction orthogonal to the deflection direction of the first deflector, a scanning lens disposed between the first deflector and the second deflector, a scanning surface for imaging the scanning beam from said scanning lens through the second deflector, and a device for moving the scanning lens in the direction of its optic axis in synchronism with the rotation of the second deflector to thereby obtain a strain-free two dimensional scanning figure on the scanning surface.

Abstract: A beam scanning device provided with a beam generator to generate beam, a deflector to deflect the beam, and a beam detector to detect the deflected beam. In this beam scanning device, while the beam detector is detecting the beam with a definite cycle, the beam generator is so controlled that the beam may be generated therefrom with such definite cycle, and the beam is constantly generated from the beam generator when the beam detector becomes unable to detect the beam with such definite cycle. By thus controlling the beam generation, the beam detection can be carried out rapidly, even when the cycle for the beam detection shifts or noises enter during the beam detection.